Added id->misc->defaulted_conf to record when a request doesn't find a
matching port so a default is chosen instead.
Compatibility note: The fallback in case there is no site with the "Default
site" flag set in the server has changed slightly: Now the configuration
with the least specific port URL is used, while in earlier versions the most
specific port URL was chosen. This is a fringe case that should only affect
badly configured servers.